73-87chevytrucks.com
General Site Info => General Discussion => Topic started by: smitty77 on September 29, 2009, 07:41:53 am
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I found a nugget of info some other rookies such as myself might need clarification on, and didn't want to threadjack Screamin86's thread.
Vile mentioned "properly seat the converter" when mating a motor to a trans. My question is, what is the proper procedure seeing as I just lowered my motor into the frame and mated it to the tranny? During the motor swap I also swapped the converter from the 2wd trans into the 4wd trans. I lined up the notch in the converter with the key on the trans shaft, slid the converter onto the splined shaft, and pushed it back as far as it looks like it should go. I ran out of daylight before I could mate the flywheel to the converter, but the trans bolted up to the engine without a hassle and there's a whisker of space between the converter and the flywheel after I torqued it all together. Anything else I need to do or am I all set?
The reason behind the converter swap is one has a different bolt pattern than the other. Will the converter from the 2wd trans (with 3 bolts attaching it to the flywheel) work in place of the beefier 7 bolt converter that came with the 4wd trans (trans was from a 3/4 ton)?
Is the TH400 the only trans to have the modulator on the side of the case? I know for sure the 4wd is a TH400. The 2wd trans also has a modulator on the side that I could spot while working in the engine bay but I haven't crawled under it to verify the pan shape.
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No the TH400 is not the only trans with a vacuum modulator.
Installing the converter, first inspect the pump bushing and seal. Make sure the neck of the converter is clean. Fill the converter and install it onto the stator support, ensure you also engage the input shaft into the turbine and the lugs on the pump. when you install the engine and trans you should be able to rotate the converter. If the engine came from a manual trans vehicle make sure you remove the pilot bearing.
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It can be a pain to get it seated in right but if you know what to "feel" for its not too bad. What ive always done is once its on the input shaft a kinda spin it slowly while pushing it towards the tranny and you will "feel" it kinda drop in sometimes you will fill it kinda drop twice and oncw you have the motor bolted up there will be roughly a 1/2 of space between the converter and the flexplate. Then you just wiggle it up to bolth them together.
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If i could extrapolate on this topic for a moment:
Let's say you are using, say, a B.O.P. adapter to , say, use a chevy motor in a car that originally had a B.O.P. trans or vice-versa. Wouldn't this mean that the converter is 1/8 inch or so (or whatever thickness the adapter plate is) more forward than normal?
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It's minimal with no problems.
(http://www.compperformancegroupstores.com/store/graphics/00000006/230000_600.jpg)
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So, in other words, there's an acceptable amount of tolerance for the converter to be back all the way vs. a little set foward?
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Correct, the converter should have axial thrust. Eccentricity and radial movement = bad.
The most important thing is to make sure the converter is fully seated. Many people make the mistake and when bolting the engine and trans together break the pump and possibly damage the converter.
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Correct, the converter should have axial thrust. Eccentricity and radial movement = bad.
The most important thing is to make sure the converter is fully seated. Many people make the mistake and when bolting the engine and trans together break the pump and possibly damage the converter.
Thanks for the response Vile and Screamin86. I'm confident I did it right, as the pump drive (is that the "key" that the slot in the converter meshes with?) was positioned at close to 3 o'clock when you're looking at the shaft from the front, so I just positioned the torque converter likewise, slid it onto the shaft, wiggled it a bit and it "dropped in" as screamin suggested it would.
Thanks again guys! Now if only this weekend was a dry as the last 3 or 4.......
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If you can't get your fingers behind the conveter (between the pump and conveter) she in all the way.
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yea , if it dropped in without spinning it, you got lucky, long as the bellhouseing mates up to the block without forcing it, you are fine, lotta people make the mistake mentioned above of not seating the converter and then forcing the bellhouseing up to the engine with the bolts, this brakes the front pump in the trans, it might work for a few min or miles, but not for long if at all. alwasy remember to give it a few spins while pushing in and feel for it to drop in . once you do it a time or two, you will get the feel for it. key is never force the trans up to the engine.